Metal and plastic tubing has come into wide spread usage in constructing racks, stands, railings, benches, tables, shelves, scaffolds, etc. for industrial, commercial and home do-it-yourself projects. Many different connectors have been devised to connect the tubing. Graham, U.S. Pat. No. 885,240, Apr. 21, 1908 and U.S. Pat. No. 885,992, Apr. 28, 1908 provided a cast bracket which connected pipe by inserting bolts through holes drilled in the pipe.
Pittaluga, U.S. Pat. No. 2,696,396, Dec. 7, 1954 and Blu, U.S. Pat. No. 2,711,917, June 28, 1955 provided connectors which in effect were clamps for joining pipes. The connectors would only take one size pipe.
Schwartz, U.S. Pat. No. 3,062,570 formed his connector from a sheet metal member but there was no positive connection between the connector and the tubular member. The pipe was held to the connector merely by the friction in the pre-bent cut-out strap-like portions.